A number of fasteners have been used in the past for securing one object on another object, as for example, securing an article on a hollow wall and disclosed in the patent art by U.S. Pat. Nos. 1,295,734, 4,500,238, 4,765,788, and 4,828,439 among others. All these patents describe two member fastening systems, where a first member is inserted in one object, while the second member is inserted first through the second object, and then into the second member, causing part of the second member to expand and thus secure the objects with respect to each other.
Since the second member, as aforementioned, supports one of the objects onto the first member, a substantial amount of force is usually exerted on said second member tending to separate the the second member from the first member, and therefore, dissolve the system. Thus, good binding between the two members is necessary, and it is usually achieved by utilizing threaded configurations, unless the friction between the first member and the second member is extraordinarily high for some reason. Such configurations may involve a female threaded portion on the first member, and a screw to be employed as a second member Despite the use of threaded configurations, however, even the screw arrangements are many times inadequate, especially in environments subjected to any type of vibration. It is very well known that vibrations cause screws to become loose, and miscellaneous mechanisms, most of which are based in increase of the friction force between the first and the second member, have been utilized in the past in attempts to prevent this from occurring. However, regardless of the relative success of these methods, the fastening system becomes more cumbersome, more difficult and more time consuming to use.
The substantial force exerted on the second member may be reduced considerably by inserting the first member through the two objects, and then inserting the second member in the first member to cause expansion and final fastening. In such occasions the force is mainly applied on parts of the first member, while the function of the second member is to maintain the first member in the expanded form. Thus, no substantial force tending to separate the two members is present. However, vibration again may cause the two members to separate, and dissolve the fastening function.
A large number of attempts have been made and tested in the past with rather limited success. When one problem is resolved, a different one arises, minimizing the final net effect.
The following U.S. patents, among many other ones, represent examples of attempts to resolve this vexing problem:
U.S. Pat. Nos. 1,601,796, 1,721,087, 3,112,547, 3,147,525, 3,357,749, 4,403,337, 4,331,413, 4,426,181, 4,647,626, 4,757,664, 4,708,552, 4,786,225, 4,832,547, 4,871,289, and 4,874,276.
Thus, it is an object of the instant invention to provide a fastening system lacking one or more of the disadvantages of the currently existing or proposed fasteners. More particularly, the different embodiments of this invention, may provide for example fastening systems which can be installed and/or disassembled easily and fast, and/or possess superior vibration proof properties, among other improvements.